This is a part of acontinuing study of the information handling aspects of the nervous system. The emphasis is on the information and its processing, rather than on the internal operation of the parts which carry this information. The study involves the motor system, including muscle, central integration, and the associated receptors. The work differs from its historical basis principally by the relatively heavy emphasis on the dynamic properties of the signals and nonlinearities in their processing and by an attempt to define more specifically the nature of the interactions between converging signals. While the goals are related to the un erstanding of biological action, methods are freely taken from engineering system analysis when they seem to offer the advantage of previously tested tools. Simulation with analog or digital computing equipment, mathematical- and graphic-analysis are all procedures taken from engnineering practice and have proven fruitful and will continue to be used in this study.